Silencer with curtain of water maintained at discharge orifice



June 10, 1969. CONARD, JR 3,448,824 I SILENCER WITH CURTAIN OF WATER MAINTAINED AT DISCHARGE ORIIFICE Filed July 5, 1968 FIG.

INVENTOR. ARTHUR BAYARD CONARD, JR.

BY 6Z9- CUM A N Y United States Patent 3,448,824 SILENCER WITH CURTAIN OF WATER MAINTAINED AT DISCHARGE ORIFICE Arthur Bayard Conard, Jr., Shreveport, La., assignor to American Machine & Foundry Company, Inc., a corporation of New Jersey Filed July 5, 1968, Ser. No. 742,759 Int. Cl. F01n 3/04 U.S. Cl. 181-52 13 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a wet type in-line silencer adaptable for use with internal combustion engines which works the vapor and its contained sound energy by expansion, contraction and reflection to reduce noise and having a curtain or Wall of water around the exit orifice to inhibit the passage of sound.

This invention relates generally to silencers or mufflers adaptable for use with internal combustion engines and more specifically to a wet type of silencer adaptable for marine use.

It is an object of this invention to provide a silencer which traps sound energy within the silencer by maintaining a wall or curtain of water around the discharge orifice.

It is another object of this invention to provide a silencer having a discharge orifice which varies automatically to satisfy operating conditions.

It is also an object of this invention to provide a silencer which performs well with various size engines operating at various speeds and under various loads.

It is an additional object of this invention to provide a silencer which subjects the vapor and its contained sound energy to expansion, contraction and reflection to reduce noise.

It is an additional object of this invention to provide a silencer which is of the in-line type to give ease of installation.

It is an additional object of this invention to provide a silencer having a reasonable pressure drop.

It is an additional object of this invention to provide a silencer having liquid lift in the exit for above waterline exhaust for marine use.

It is still another object of this invention to provide a silencer which is reliable in operation and economical to build.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the invention becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a side sectional view of structure in accordance with the principles of the invention;

FIG. 2 is a view along the line 2-2 of FIG. 1;

FIG. 3 is a view of another form of structure in accordance with the principles of this invention; and,

FIG. 4 is an end view of the structure of FIG. 3.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring to FIG. 1, a cylinder 10 which can be composed of metal, plastic, Fiberglas or the like supports two end caps 12, 14 which can also be composed of metal, plastic, Fiberglas or the like. In those instances where the 3,448,824 Patented June 10, 1969 cylinder 10 and the end caps 12, 14 are of metal, the end caps can be crimped, welded, or brazed to the cylinder to form a permanent gas and liquid tight connection. Where the end caps and cylinders are of plastic or fiberglas, than a bonding adhesive which will not be adversely aifected by the heat, vibration and water conditions encountered during operation of the silencer can be used to form permanent gas and liquid tight connections.

The end cap 12 supports a centrally positioned cutout through which is positioned an inlet pipe 16 having an upward bend. The end cap 14 supports a centrally positioned cutout through which is positioned an outlet pipe 18 having a downward bend. The inlet pipe 16 and outlet pipe 18 are secured to their respective end caps in a permanent gas and liquid tight manner. If desired, internal or external pipe threads can be cut or formed into the inlet pipe 16 at the end 20 and into the outlet pipe 18 at the end 21 to facilitate connecting the silencer to the exhaust of an engine.

The cylinder 10 is divided into two chambers 22 and 24 by a plate 26 having a bottom positioned cutout 28 and a centrally positioned cutout 30. The area of chamber 22 is sized to be substantially seven-twelfths of the area of the cylinder 10; and, the area of chamber 24 is sized to be substantially five-twelfths of the area of the cylinder 10.

The centrally positioned cutout 30 of the plate 26 supports a tube 32 positioned to project substantially three-fourths of its length into chamber 22 and one-fourth of its length into chamber 24.

A control shaft 34 which can be secured to the wall of the cylinder 10 or to drain plug 36 threaded into the wall of the cylinder 10 is centrally positioned Within downwardly facing orifice 38 and projects into the pipe 18,

Referring to FIG. 2, there is illustrated the centralpositioning of the control shaft 34 relative to the orifice 38 in addition to the cutout 28 in plate 26. It is to be understood that, if desired, a number of small size circular openings can be substituted for the cutout 28.

In some circumstances it may be desirable to provide a control shaft 34 which is an integral part of pipe 18. Referring to FIGS. 3 and 4 there is illustrated an embodiment wherein the control shaft 34 is centrally aligned within the tube 18 positioned to extend partially into the tube and partially out of the tube and supported rigidly by a web member 39. The arms of the web member can be of thin material or contoured to present a minimum of turbulance to flow over and around the web.

In operation the silencer is connected to the exhaust system of a marine type of internal combustion engine wherein the exhaust gas is mixed with cooling water.

The mixture of exhaust gas and cooling water is fed to the pipe 16 wherein the mixture is directed upward and impinges upon the wall of the cylinder 10. The Water wets and flows down the walls of chamber 22 and collects at the bottom of the cylinder. The water then flows through the bottom positioned cutout 28 of plate 26, the cutout 28 being sized to permit the surface of the water to rise above the cutout 2-8 and contact the plate 26. The plate 26 helps stabilize or quiet the surface of the water which has passed under the plate 26 and flows into chamber 24.

The exhaust gas vapor portion of the mixture of gas and water which emerges from the pipe 16 separates from the liquid in chamber 22. The vapor expands in chamber 22, fio-ws through tube 32 where it is choked, and then flows into chamber 24 where it again expands.

The vapor then flows into the orifice 38, through the pipe 18 and out to the atmosphere.

Under normal operating conditions, the fluid level attempts to build up or rise within chambers 22 and 24 of the cylinder 10. However, as the vapor flows into the orifice 38 it scoops liquid up from the surface of fluid which has collected in chamber 24 and carries it upward through the orifice 38 and the tube 18. The removal of water by the vapor entering the orifice 38 is self regulating as the vapor scoops the liquid at a rate required to maintain a clearance between the orifice 28 and the surface of the liquid in chamber 24 suflicient to enable the vapor within the silencer to escape.

The control shaft 34, one end of which is positioned below the surface of the liquid in chamber 24, and the other end extending through the orifice 38 and into the tube 18, reduces the area of the orifice 38 and thus help urge the escaping vapor and its contained water to form a tubular curtain of water which extends from the surface of the water in chamber 24 to the orifice 38; the tubular curtain of water being around the inside wall of the orifice 38.

The plug 36 in the wall of the cylinder is used to drain all water from the cylinder during cold weather shut down or storage.

The forming and maintaining of a tube or peripheral wall or curtain of water extending from the surface of the water up into the tube 18 blocks noise within the chamber 24 from passing out through tube 18. The variable exit orifice, that space present between the orifice 38 and the surface of the water is self-adjusting and enables the silencer to perform efliciently with various engine sizes operating with various loads and at various speeds. The two chambers and the interconnecting choke tube 32 work the vapor and its contained sound energy by expansion, contraction and reflection to reduce noise. The flooding or blanketing of the inside surface of the wall of chamber 22 with water helps reduce the transmission of noise through the walls of the silencer. The plate 26, the lower edge of which extends below the surface of the water which collects at the bottom of the cylinder 10 helps to provide a smooth surface to the water in chamber 24. The control shaft 34 which extends from below the surface of the Water in chamber 24 up through the orifice 38 modifies the velocity profile in the exit tube 18. The maximum velocity is moved from the center of the tube to the middle of the circular annulus formed by rod 34 and the exit tube 18. By this means a circular curtain of water is formed in the exit tube 18 and is located adjacent to the Wall of the tube. Thus, sound energy to exit the unit, must pass through the circular curtain or wall of water. The wall of water entraps the sound energy in the silencer and allows it to rework and interact on itself to decrease the sound.

In one application, a silencer built in accordance with the principles of this invention and which operated in a very satisfactory manner had the following dimensions.

Referring to FIG. 1, the inlet pipe 16 and outlet pipe 18 were sized to accommodate a one and one-half inch fitting; cylinder 10 had a diameter of five and three-fourths inches and a length of twelve inches. The plate 26 was spaced substantially seven inches from the inlet end and five inches from the outlet end of the silencer; and the choke tube 32 which was four inches long was positioned centrally within the plate 26, three inches of the choke tube projecting into the chamber 22 and one inch of the choke tube projecting into the chamber 24. The cutout 28 in the bottom portion of the plate 26 provides a clearance between the wall of the cylinder 10 and the plate 26 of substantially one-half of an inch through which the water in the chamber 22 can flow to the chamber 24. Under normal operating conditions, the level of the water within the cylinder is above the cutout 28 and the orifice 38 of the tube 18 is positioned substantially one inch above the bottom of the cylinder 10.

To minimize corrosionproblems where metal is used,

the inside and outside surfaces of the silencer can be coated with an appropriate rust inhibiting agent.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is:

1. A silencer comprising a first chamber, an entrance means coupled to said first chamber to direct a mixture of fluid and gas into said first chamber, the fluid being directed against a wall of said chamber, a second chamber, first passage means interposed between said first chamber and said second chamber to pass gas from said first chamber to said second chamber, second passage means interposed between said first chamber and said second chamber to pass fluid from said first chamber to said second chamber, an exit means coupled to discharge a mixture of fluid and gas from said second chamber, and shaft means projecting into said exit means to define a cylindrical path for the fluid and gas entering the exit means.

2. The structure of claim 1 wherein said first passage means comprises a tube to choke the gas as it passes from said first chamber to said second chamber.

3. The structure of claim 2 wherein said second passage means is interposed between the bottom of said first and said second chambers.

4. The structure of claim 3 wherein said first chamber is larger than said second chamber.

5. The structure of claim 4 wherein said tube to choke the gas projects into said first chamber and said second chamber.

6. The structure of claim 5 wherein said tube projects into said first chamber a distance greater than sald tube projects into said second chamber.

7. The structure of claim 6 wherein said shaft means extends from said exit means to below the surface of water which would be present in said second chamber during operation.

8. The structure of claim 7 including support means coupled to axially align said shaft means with said exit means.

9. The structure of claim 8 wherein said support means comprises arm members extending from said shaft means to said exit means.

10. The structure of claim 7 wherein said entrance means comprises a pipe having a bend within said first chamber oriented to direct a mixture of fluid and gas towards an upper surface of said chamber.

11. The structure of claim 10 wherein said exit means comprises a pipe having a bend within said second chamber oriented to receive a mixture of fluid and gas from a lower surface of said chamber.

12. The structure of claim 8 wherein said support means comprises a drain plug removable coupled to the wall of said second chamber and coupled rigidly to said shaft means.

13. In a silencer, a cylinder, a first end cap coupled to close one end of the cylinder, a second end cap coupled to close the other end of the cylinder, a plate coupled to divide said cylinder into a first chamber and a second chamber, said first chamber being larger than said second chamber, an entrance pipe extending through said first end cap into said first chamber, the end of said entrance pipe positioned within said first chamber having a bend oriented to direct a mixture of fluid and gas toward an upper surface of said first chamber, an exit pipe extending through said second end cap into said second chamber, the end of said exit pipe positioned within said second chamber having a bend oriented to receive a mixture of fluid and gas from said chamber, a shaft axially aligned with said exit pipe and extending from said exit pipe to the water which would be present in said second chamber during operation, a choke tube supported by said plate to pass gas from said first chamber to said second chamber,

,5 6 and a cutout in the bottom of said plate to pass fluid from 1,546,197 7/1925 Brown 181-52 XR said first chamber to said second chamber. 2,360,429 10/1944 Leadbetter.

- 2,692,653 10/1954 Diez 18 1--S 2 References Cited UNITED ST P 5 S. WARD, JR., Primary Examiner. 1,061,775 5/1913 Newton et a1 181-57 XR 181 57 

